From e1cb15807e17a015853c61e10d532c9a55d0056e Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@victoriametrics.com>
Date: Thu, 11 Aug 2022 21:37:21 +0300
Subject: [PATCH] app/vmselect/netstorage: improve scalability of blocks
 processing on systems with multiple CPU cores

Previously a single syncwg.WaitGroup was used for tracking the lifetime of processBlock callbacks
across all the per-vmstorage goroutines. This could be slow on systems with many CPU cores
because of inter-CPU synchronization overhead.

Use a separate per-vmstorage sync.WaitGroup instead in order to reduce inter-CPU synchronization overhead.
This should imrpove performance for heavy queries over big number of blocks on multi-CPU systems.
---
 docs/CHANGELOG.md | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 105f59c1a3..4ab54883e9 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -15,7 +15,9 @@ The following tip changes can be tested by building VictoriaMetrics components f
 
 ## tip
 
-* SECURITY: [vmalert](https://docs.victoriametrics.com/vmalert.html): do not expose `-remoteWrite.url`, `-remoteRead.url` and `-datasource.url` command-line flag values in logs and at `http://vmalert:8880/flags` page by default, since they may contain sensitive data such as auth keys. This aligns `vmalert` behaviour with [vmagent](), which doesn't expose `-remoteWrite.url` command-line flag value in logs and at `http://vmagent:8429/flags` page by default. Specify `-remoteWrite.showURL`, `-remoteRead.showURL` and `-datasource.showURL` command-line flags for showing values for the corresponding `-*.url` flags in logs. Thanks to @mble for [the pull request](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/2965).
+* SECURITY: [vmalert](https://docs.victoriametrics.com/vmalert.html): do not expose `-remoteWrite.url`, `-remoteRead.url` and `-datasource.url` command-line flag values in logs and at `http://vmalert:8880/flags` page by default, since they may contain sensitive data such as auth keys. This aligns `vmalert` behaviour with [vmagent](https://docs.victoriametrics.com/vmagent.html), which doesn't expose `-remoteWrite.url` command-line flag value in logs and at `http://vmagent:8429/flags` page by default. Specify `-remoteWrite.showURL`, `-remoteRead.showURL` and `-datasource.showURL` command-line flags for showing values for the corresponding `-*.url` flags in logs. Thanks to @mble for [the pull request](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/2965).
+
+* FEATURE: [VictoriaMetrics cluster](https://docs.victoriametrics.com/Cluster-VictoriaMetrics.html): improve performance for heavy queries on systems with many CPU cores.
 
 * BUGFIX: prevent from excess CPU usage when the storage enters [read-only mode](https://docs.victoriametrics.com/Cluster-VictoriaMetrics.html#readonly-mode).